If a customs officer at the European airport you are departing from refuses to stamp your receipts, you can get the customs stamp at your non-EU airport of arrival instead.
At your non-EU airport of arrival, you can:
1. go to the customs office where you can 'declare your goods'. These offices are located between the bagage claim belts and the exit.
2. go to a customs office after the exit. Customs offices are often located in departure halls close to check in. Ask an airport employee to point you in the right direction.
Please note; if there is no date included in the stamp, please ask the customs official providing the stamp to write the date of entry with a signature next to the stamp.